Hone or Strop Burr from Edge of Sharpened Tool
When a tool is sharpened, a fine burr forms on the edge. If you test the tool on wood before removing the burr, it will dull the edge with the burr. Even light use will cause this to happen. If you are not already doing so, after sharpening the tool, remove the burr by stropping or honing with a slip stone.